Ron's 914, High oil temp Options

[Ron914]

Glad the "force it" approach was able to get it there. Not ideal but hey, it works!


I suspect something may be bent slightly and that you may still be loosing a bit of cooling air over the cooler as the temps are a touch higher than I would expect but well within what the oil should be able to handle.

As for how its running

13.5-13.8 AFR at idle is most likely where its going to be the strongest.
If you are seeing anywhere in the 13s full warm I would say you are doing well.


14 while driving, depending on the circumstances, is on the lean side at least from a head temp standpoint. between 14 and 15 is where heads get the hottest. Above or below that range things cool off but a stock d-jet distributor wont allow you to go leaner than 15 properly.

Now that you have a working head temp gauge though I would say if it aint broke, dont fix it. ie, if the conditions you are driving under when AFRs are hitting 14 are not creating excessive head temps or drivability issues, I wouldn't touch it. MPS are extremely touchy and if the car is driving fine now you are just as likely to make things worse toying with it. Main thing you want to worry about as far as AFRs go is under load. 14 under heavy throttle is no good, you really want to see mid to high 12s there, generally not much leater than 13.0

Hi James ,
Thanks for the AFR numbers , I will need to drive more to see what kind of consistent values I am getting while watching the cylinder head temperatures.

Do you have a critical temp for the heads ?

I played with the knob on the ECU and it seems to raise and lower the AFR readings a little bit .

If I needed to adjust something to bring up load AFR readings a bit could I do that with the knob on the ECU?

[Ron914]

EXCELLENT!! Good work staying with it.

Thanks Brian

[Ron914]

Later this week I am going to get back to the flaps problem .

I will pull #4 plug again and look with the scope to see how much the flap is down over the cooler.

Then see if I can move that guide piece of tin that the flap is hitting towards the left and see if it still restricts the flap movement

Right now though I am enjoying the car for sure .

[emerygt350]

For anything below 6 mmhg you can just dial the full load stop out. A quarter turn counterclockwise is a big change so don't turn it more than that before checking wot afr again.

[gonzo54]

Well looks like you all were correct .The wires were hooked up wrong on the CHT . I corrected the wiring and everything is reading as it should in F now .Took the car for a 50 minute drive ,even got on the freeway for a few miles . My car is finally a driver (IMG:style_emoticons/default/piratenanner.gif)

Thank you to everyone who has offered me advice and guidance . I could not have completed this project without the help of the 914 Community .

I still have to get the flap corrected but for now I think I am getting sufficient cooling .

I also need to start a new challenge of dialing in my MPS but I must say the car is running fairly strong .

Time to close this chapter and move on to the next chapter.

Thank you
Ron

Congratulations! Problem’s solved-looking forward to many So Cal drives with you guys!

[Montreal914]

Congratelations Ron! (IMG:style_emoticons/default/smilie_pokal.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/cheer.gif) (IMG:style_emoticons/default/beerchug.gif)

[JamesM]

Glad the "force it" approach was able to get it there. Not ideal but hey, it works!


I suspect something may be bent slightly and that you may still be loosing a bit of cooling air over the cooler as the temps are a touch higher than I would expect but well within what the oil should be able to handle.

As for how its running

13.5-13.8 AFR at idle is most likely where its going to be the strongest.
If you are seeing anywhere in the 13s full warm I would say you are doing well.


14 while driving, depending on the circumstances, is on the lean side at least from a head temp standpoint. between 14 and 15 is where heads get the hottest. Above or below that range things cool off but a stock d-jet distributor wont allow you to go leaner than 15 properly.

Now that you have a working head temp gauge though I would say if it aint broke, dont fix it. ie, if the conditions you are driving under when AFRs are hitting 14 are not creating excessive head temps or drivability issues, I wouldn't touch it. MPS are extremely touchy and if the car is driving fine now you are just as likely to make things worse toying with it. Main thing you want to worry about as far as AFRs go is under load. 14 under heavy throttle is no good, you really want to see mid to high 12s there, generally not much leater than 13.0

Hi James ,
Thanks for the AFR numbers , I will need to drive more to see what kind of consistent values I am getting while watching the cylinder head temperatures.

Do you have a critical temp for the heads ?

I played with the knob on the ECU and it seems to raise and lower the AFR readings a little bit .

If I needed to adjust something to bring up load AFR readings a bit could I do that with the knob on the ECU?

Head temps, worst case on d-jet cars seeing ~380 under sustained load is not unusual but you generally dont want to let them get much hotter than that if it can be avoided. 400+ is where you should worry.

The ECU knob only impacts mixture at idle.

While we know how to do it now, and it can be done, D-jet wasn't designed to be adjusted. The early cars didn't even have idle adjustment knobs. From the factory point of view parts are either in spec or they are not.

[emerygt350]

Glad the "force it" approach was able to get it there. Not ideal but hey, it works!


I suspect something may be bent slightly and that you may still be loosing a bit of cooling air over the cooler as the temps are a touch higher than I would expect but well within what the oil should be able to handle.

As for how its running

13.5-13.8 AFR at idle is most likely where its going to be the strongest.
If you are seeing anywhere in the 13s full warm I would say you are doing well.


14 while driving, depending on the circumstances, is on the lean side at least from a head temp standpoint. between 14 and 15 is where heads get the hottest. Above or below that range things cool off but a stock d-jet distributor wont allow you to go leaner than 15 properly.

Now that you have a working head temp gauge though I would say if it aint broke, dont fix it. ie, if the conditions you are driving under when AFRs are hitting 14 are not creating excessive head temps or drivability issues, I wouldn't touch it. MPS are extremely touchy and if the car is driving fine now you are just as likely to make things worse toying with it. Main thing you want to worry about as far as AFRs go is under load. 14 under heavy throttle is no good, you really want to see mid to high 12s there, generally not much leater than 13.0

Hi James ,
Thanks for the AFR numbers , I will need to drive more to see what kind of consistent values I am getting while watching the cylinder head temperatures.

Do you have a critical temp for the heads ?

I played with the knob on the ECU and it seems to raise and lower the AFR readings a little bit .

If I needed to adjust something to bring up load AFR readings a bit could I do that with the knob on the ECU?

Head temps, worst case on d-jet cars seeing ~380 under sustained load is not unusual but you generally dont want to let them get much hotter than that if it can be avoided. 400+ is where you should worry.

The ECU knob only impacts mixture at idle.

While we know how to do it now, and it can be done, D-jet wasn't designed to be adjusted. The early cars didn't even have idle adjustment knobs. From the factory point of view parts are either in spec or they are not.

He has the tangerine racing plug and tool so tuning is possible. He also has afr and a vacuum gauge so tuning is not going to be blind. His numbers look good already so a little wot adjustment is the easiest kind.

[JamesM]

He has the tangerine racing plug and tool so tuning is possible. He also has afr and a vacuum gauge so tuning is not going to be blind. His numbers look good already so a little wot adjustment is the easiest kind.

It for sure can be done, I have rebuilt quite a few MPSs. Adjustments can be rather touchy however and instantaneous AFR readings are not an optimal way to tune.

Even adjusting an MPS to documented inductance numbers isnt reliable beacuse they vary with atmospheric conditions, reading a dial on a vacuum pump isn't accurate, and there can be variance between inductance meters. The only way I trust to do it is to clone an unmolested known good reference unit using a T'd vacuum source in order to ensure identical readings through the entire vacuum curve.


If someone is seeing 14:1 under sustained full load you would probably want to correct that, while 14:1 under light cruise, decell or during transients isn't really anything to be concerned about in and of itself. You also want to know 100% that the reading you have on your AFR gauge is accurate and that's where things get tricky. When I was at PMB near 100% of 914s came in with some sort of exhaust leak, and this will cause and AFR gauge to read falsely lean under certain operating conditions. The issue is pronounced enough that recently while tuning @BillC car remotely from logs I identified an exhaust leak he didn't know he had just based on data logs and the shape his fuel map was taking on. You cant blindly trust a single gauge.

If its running hot its a problem, if there are drivability issues its a problem. Power output plateaus over a wide range of AFRs though so assuming the AFR readings you are looking at are perfect the adjustment from 14:1 to 12.8:1 might gain you somewhere in the range of 2% peak HP, though at a much greater cost to fuel economy.

What I am saying is if there are no symptom someone is trying to address beyond a number on an AFR gauge it may not be worth messing with as people have often caused themselves more problems than they have solved. If it drives good, if temps looks good, if plugs look good, I wouldn't mess with it.

[emerygt350]

I was going to say if the temps look good and the mpg is where you want it, you are fine, but eventually you got there. Although I would add, I am not at all afraid of playing with mine and do all the time. It takes two minutes to pull it and reset it to a known good state if you have taken the time to record the curve before you start playing. When I get to a tune I am liking I pull it and record the curve and pop it back in the car. Really nothing to be afraid of.

[JamesM]

I was going to say if the temps look good and the mpg is where you want it, you are fine, but eventually you got there. Although I would add, I am not at all afraid of playing with mine and do all the time. It takes two minutes to pull it and reset it to a known good state if you have taken the time to record the curve before you start playing. When I get to a tune I am liking I pull it and record the curve and pop it back in the car. Really nothing to be afraid of.

Im an engineer... I can be very verbose (IMG:style_emoticons/default/biggrin.gif)

If you already have the MPS drilled and futzed with then not much harm giving it a little tweak so long as you understand how it impacts the fueling curve.

without a problem to chase though just seems an unnecessary roll of the dice. If you adjust it just to turn a gauge reading of 14 to a gauge reading of 12 and it turns out the gauge wasn't accurate then you wind up with black smoke and possibly even ring wash.

From the numbers Ron posted it sounds like he is butting up against the limits of where you want to be as far as AFRs on both ends. 11s cold is about the limit on the rich side, get into the 10s and you get black smoke. Leaner than 14s on cruise and you start to break up without additional ignition advance which you cant accomplish with d-jet. I question the accuracy of the 14 reading which is why I wouldn't want to tune anything based on just that. Complicating things is that being rich during warm up very likely isnt an MPS issue at all but tweaking the MPS will still impact it. We still need to know head temps and what the AFR numbers look like under full load when fully warm, that is really what I would use to make the call as to if an adjustment is warranted. A true reading of 14:1 floored going up a hill may be worth addressing, but I would be looking to richening that up, and he suspects he is already rich. To many questions.

[emerygt350]

Yeah, time will tell. He is also probably running a bit more compression than stock with his 2056 so that can muddy the waters as well. Seems to be doing well at the moment though. If hot afrs look good I would back out the full stop teeny bit. If it is looking lean when hot across the board I would give the inner a little counterclockwise tweak but it looks pretty good there at the moment.

Make sure it is nice and warm before you do any adjusting. And if you haven't already you should record the curve on your mps as it is. I do 2 mmhg increments from 2 - 26. No need to go as high as I do if your engine has normal vacuum levels.